Optimal Frequency of Patient Monitoring and Intensity of Oral Anticoagulation Therapy in Valvular Heart Disease.

The antithrombotic effect of oral anticoagulation therapy and the incidence of anticoagulant-related bleeding complications are both closely correlated with the intensity of treatment. The optimal intensity of oral anticoagulation for an individual patient is the target INR that results in the lowest incidence of thromboembolic plus bleeding complications. For patients with native valve lesions, one must consider the cardiac morphology and pathophysiology, for example, the etiology of the disease, left atrial diameters, loss of active atrial contraction (atrial fibrillation), left ventricular pump function, and left ventricular diameters, to determine an optimal INR target. In patients with prosthetic devices, the "thrombogenicity" of the heart valve prosthesis is an additional risk factor for intracardiac thrombus formation and thromboembolic episodes. This "thrombogenicity" may vary significantly from device to device. INR self-testing improves the overall prognosis of patients on lifelong oral anticoagulation therapy because patients remain more precisely within that target therapeutic INR range. For most patients under phenprocoumon, one to two INR measurements per week are a sufficient frequency to provide a stable intensity of anticoagulation.